It has been useful to prepare cathodes, often known as air cathodes, by using mixtures of carbon black with a polymeric binder and to prepare such materials in sheet form. The sheet can also include activated material. Thus, for example, in U.S. Pat. No. 4,354,958 it has been shown to make an active layer for an electrode of improved strength that can contain carbon black and fibrillated Polytetrafluoroethylene particles, which electrode can be activated by platinum catalyzed active carbon particles. This active layer is laminated to a backing layer and the laminate may serve as an active electrode.
It has also been known to prepare these laminated electrodes by having screens pressed into the surface of the laminate. As disclosed in U.S. Pat. No. 3,456,113, one screen can be used with the active layer and another screen with the backing layer.
Or the carbon electrode might be pressed against a conductive foil and a separator in a battery arrangement using a consumable electrode, e.g., zinc plate electrode. In U.S. Pat. No. 4,115,626 there is shown a representative cell. To provide interconnected elements the zinc electrode is enclosed in a synthetic plastic frame.
It has also been found useful to provide electrolyte-absorbing layers as part of the interconnected layers in a battery construction. For example, in U.S. Pat. No. 3,598,655 such absorbing layers are shown to be useful between a consumable metal anode plate and a planar cathode comprising a coated screen. As shown most particularly by the patent drawing, essentially all of the battery elements can be bound into a casing. Or as disclosed in U.S. Pat. No. 3,518,123, a casing can support electrodes wherein the consumable electrode may be wrapped in an inert, non-consumable material. The construction will ostensibly retard premature dehydration of the battery.
More recently in U.S. Pat. No. 4,246,324 box-like forms have been used with electrodes being on opposing faces of the form. Electrolyte is maintained between the facing electrodes and the consumable anode can be of plate shape, for example held in place on the box wall by spring clips. Then in U.S. Pat. No. 4,551,399, the anodes are shown tapered and adjacent structure includes slotted walls and cathodes with alternating spaces and projections.
It has also recently been shown in U.S. Pat. No. 4,551,399 that the cathode can be mounted on arms, and the arms wired. The arms can then penetrate through a separator wall and thereby be in contact with an anode on the far side of the wall. The anode may be wedge shaped with the backside conforming with the straight separator wall and the angled side being in a plane parallel to the plane of the cathode.
It has also been proposed to affix a cathode having surface screen reinforcement to a cell body by using combination techniques including welding and application of adhesive to thereby adhere the grid to the cell body. To further tighten the seal, intrusive members, e.g., screws, have also been taught to be useful.
In all such structures there is however still considerable room for improvement for providing elements tightly sealed, yet maintaining good electrical contact. It would also be desirable to provide interconnected structure, all of which can be readily inserted and removed, e.g., for repair, without damage or loss to closely associated cell members. It would furthermore be most desirable to couple this with enhanced start-up of operation.
There has already been discussed in U.S. Pat. No. 4,379,034 the potential for undesirable start-up of an oxygen electrode which is overcome by a break-in procedure. However, it would still be desirable to obtain a most economical start-up approaching realistic operation. This could help obviate a break-in procedure, i.e., a reduced electrolyte flow and low current density procedure, that may be coupled with a lower than normal oxygen flow rate.